S. Mahunka szerk.: Folia Entomologica Hungarica 60. (Budapest, 1999)

DISCUSSION Of the four species of Oligoneuriella found during the collectings of larvae, O. keffermuellerae and O. polonica are new to the fauna of Hungary. The finding of O. keffermuellerae is especially interesting, as it is its first record from the Carpathian Basin. It was found in the Rába river only, between Könnend and Sárvár, in coexistence with O. pallida in all cases. The occurence of O. polonica is not surprising, because it was already known from the adjacent Slovakia. It was found in a few localities of the upper reaches of the Tisza river. O. pallida was found in the Dráva and Rába; O rhenana in the Gyöngyös, Rába and upper reaches of the Tisza. The Rába is home to three species (O. keffermuellerae, O. pallida, O. rhenana), the Tisza is to two (O. polonica, O. rhenana), the Dráva and the Gyöngyös are to one each (O. pallida and O. rhenana, respectively). The records are depicted in Fig. 1. O. keffermuellerae and O. pallida were found in the middle and lower reaches of the rivers, in the slow-running water near the riverside, while the rheophilous O. rhenana was collected in the upper reaches of the rivers. This is well demonstrated by the arrangement of the localities along the Rába. Sowa (1975) mentioned O. polonica from slow-running rivers with sandy bottom. However, we collected it, along with O. rhenana, from large pebbles of the gravelly bottom of the fast-running stretches of the Tisza. Table 1 shows that O. pallida is easily distinguishable by the spines situated throughout the fore tibia, while O. keffermuellerae is distinctive because of the length ratios of the gills. Males of O. polonica és O. rhenana may be separated by the shape of eyes. Differences of the females are illustrated by the drawings of abdominal segments of 8 and 9 (Figs 2-4). Mature larvae are much easier to identify; the proper time for collecting them is in July and August. N Table 1. Key to the larvae of the Oligoneuriella species of Hungary. Based on Sowa (1973), Kluge (1997) and own results O. pallida 0. keffermuellerae 0. polonica O. rhenana 1 spines some spines some spines some spines throughout in distal part in distal part in distal part 2 with short bristles with short bristles with long soft hairs with long soft hairs 3 patterned patterned unicoloured unicoloured 4 1=2 1 <2 1 >2 1 >2 5 1 : 1 1 : 1.7 1 :2 1 : 2.5 6 9.1, 11.5 12.1, 15.5 10.9, 13.5 13.4, 15.6 7 surpassing surpassing surpassing not surpassing 1: spines of dorsal side of fore tibia, 2: basal half of posterior margin of middle and hind femora, 3: pigmentation on body, 4: relation of the length of gill blades of abdominal segment 1 to 2, 5: ratio of the length of the middle tarsus to tibia, 6: average of the body lengh of full-grown larvae, without caudal filament and cerci (male, female), 7: eyes of rull-grown male larva surpassing outline of head or not.